Particle therapy systems use an accelerator to generate a particle beam for treating afflictions, such as tumors. In operation, the particle beam is accelerated inside a cavity of the particle accelerator, and removed from the cavity through an extraction channel. To track the extraction channel, the particle beam must be properly energized. Not enough energy, and the particle beam can collide with the inner edge of the extraction channel. Too much energy, and the particle beam can collide with the outer edge of the extraction channel. The result is that the particle beam is prevented from escaping the extraction channel, or the portion of the particle beam that does escape is compromised, thereby reducing treatment effectiveness.
Movement of the particle accelerator can affect the amount of energy in the particle beam that is received at the extraction channel.